As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems, such as desktop or notebook computers, are commonly provided with external interfaces for exchanging data and/or power with various types of external or peripheral devices such as portable music devices (MP3 players), personal data assistants (PDAs), cellular phones, etc. For example, an information handling system may be provided with a dedicated external charge or energy port for redirecting power from the power source of an information handling system to a second device that is coupled to the information handling system via the port. Other examples of external interfaces include Universal Serial Bus (USB) and IEEE 1394 (“Firewire”) based serial bus interfaces. Such serial bus interfaces have power transmission pins that allow external or peripheral devices to be powered and/or charged from an external port of a desktop or notebook computer, but also have other pins to provide data transmission capabilities via the same port. Design standards for the USB serial bus interface have been implemented, for example, by Windows Hardware Quality Labs (WHQL) and USB Special Interest Group (e.g., USB2.0).
In some desktop computer system configurations, power to a USB or Firewire serial bus interface of the system is made always available to the power transmission pins of the port, regardless of system state and without any system awareness the serial bus power state. In some desktop and notebook computer systems, power to a USB or Firewire serial bus interface of the system is only made available to the power transmission pins of the port when the system is powered on, again without any system awareness of the power state. Furthermore, an external or peripheral device may completely drain the battery of a notebook computer system through the power transmission pins of a USB or Firewire serial bus interface when the notebook computer is operating on battery power and is not externally powered.